1. Field of the Invention
The invention relates to a device for exploiting rock materials, ores, coal or the like, comprising rotating tools being rotatably supported on a cantilever arm which can be lifted and lowered, and relates in particular to an openpit mining device comprising rolls or heads being arranged in transverse relation to the longitudinal axis of the cantilever arm and being equipped with bits.
2. Description of the Prior Art
Such known openpit mining de frequently comprise their own chassis, in particular an endless ground engaging track equipped chassis, and can be moved by an individual drive means. As is the case in connection with underground mining machines, the chassis can have connected thereto a loading equipment oriented in a direction towards material to be excavated and seizing the excavated material and transporting this material onto conveyors. The known openpit mining devices have in common that the cantilever arm is only swivellable around an approximately horizontal axis and thus exclusively in a height direction. In any given position of the machine, its working width is restricted to the width of the excavating tools, and for the purpose of covering a greater width, the openpit mining device must be moved and be brought into a new position. If the known machine were equipped with a plurality of cutting heads or rolls being arranged one beside the other as seen in axial direction, there were frequently used several drive motors, each of which was used to drive a maximum of two rolls arranged one beside the other as seen in direction of the axis of rotation, to be in the position to keep small the distance between adjacent rolls as required for the necessary gearing. However, there remained, when operating such devices, a rock rib between rolls or heads located adjacent as seen in direction of the axis of rotation, which rib was predetermined by the dimensions of the gearing. Therefore, these rock ribs had to be removed or crushed by means of separate tools or scrapers which was varyingly expensive in dependence on the properties of the rock. If, when working with the known device, the support was shifted in the lateral direction during downward cutting work, it was possible to continuously crush the ribs without separate equipment inasfar as the lateral angle of slope was adjusted to be sufficiently flat. Adjustment of steep lateral angles of slope, in particular of lateral slopes having an essentially vertically extending edge, was not easily possible with the known device.